The first computer I ran (SuperNova,1971), we lost all power about once a week. In order to recover, I had to “toggle in” about one hundred 16-bit instructions using 16 toggle switches to boot the computer up. Those instructions taught the computer how to read from the first sector of the disk (10MEG swappable hard drive!) which contained enough information to tell the machine how to read the rest of the disk and retrieve the remaining part of the operating system. (This is why it is called boot-strapping the computer) Of course, a single bit of those first instructions being wrong would cause total failure.
I still miss having the 16 switches (plus about a dozen more) on the front panel of a “real” computer. I also miss the comforting rows of “blinking lights”, one for the “address” and one for the “instruction” there, that constantly changed as the computer was running, as well as the ability to “Pause” the computer at any time and step through instructions. For some reason a computer doesn’t seem “real” to me without that ability.
I have also punched in octal, but that was a couple years later, on a PDP machine, as well as years after that on a CPM computer.